I posted this inside a thread over in the Suggestions forum.. but it's actually a bug:

I did a combination of searches on the word "subforums":

• Selected "All Forums", Result: correct listing of two entries in subforum 1 and subforum 2.
• Selected the category "Testing Forums", Result: incorrect results of nothing found.
• Selected "Test Forum 2", Result: Nothing found. This is the nesting search capability I'd like to have added.
• Selected "Subforum 1", Result: correctly found 1 entry
• Group Selected "Test Forum 1, Test Forum 2, Subforum 1, Subforum2", Result: Correctly found 2 entries.
• Group Selected "Testing Forums category, Test Forum 1, Test Forum 2, Subforum 1, Subforum 2", Result: incorrectly found no entries

It appears the category search doesn't work, and even corrupts the search if the category is added to a group search.

Thanks for the report. After I finish up these private topic changes I'll tackle the search bugs.

These should all be fixed for the next update, alpha7.